As is known in the art, the public switched telephone network (PSTN) connects two or more telephones in a telephone call. A telephone call generally includes two parts, a signaling portion and a real-time portion. The signaling portion is used to connect the telephone call, for example, to ring a telephone, and the real time portion is used to convey a communication, for example, a voice communication. The real-time portion is typically referred to as media. The media in a voice communication typically includes one or more of voice signals, fax signals, video signals, and voice-band modem data.
The signaling portion and the real time portion carried on the PSTN during a telephone call originate as analog signals from the conventional telephones, and can be converted to digital signals and back to analog signals within portions of the PSTN during transport of the signals from one conventional telephone to another.
There are a variety of signal formats associated with the PSTN. For example, the format of the signals can be Integrated Services Digital Network (ISDN) format in other parts of the PSTN. Parts of the signaling portion conventionally have different names depending upon the format, but each format has parts with similar functions. For example the signal used to ring a telephone in ISDN is a “setup” message. For another example, a signal generated when a telephone is answered is a “connect” message in the ISDN format.
It will be recognized that the PSTN is not the only type of network that can carry telephone calls. For example, Voice over Internet Protocol (VoIP) allows voice communications to be carried on a digital network capable of Internet Protocol (IP) communications, for example, the Internet. Signals within VoIP can have functions similar to those described above. For example, VoIP can include session initiation protocol (SIP) signals capable of ringing an Internet telephone or alerting an Internet-connected personal computer (PC), and also signals adapted to indicate that the Internet telephone or the PC has been answered by a person.
As is also known, in order to place a telephone call, whether through the PSTN or through a digital network capable of VoIP communications, a telephone caller can dial a telephone number, for example, by repeatedly rotating a telephone dial or by pushing buttons on a telephone keypad. Often, the telephone caller, before placing the telephone call, is not able to determine whether the person to whom the telephone call is placed is available to receive the telephone call.
When the telephone caller wants to arrange a telephone call with another person at a future time and date, the telephone caller can first call the person in order to arrange the specified time and date at which to place the telephone call. At the specified time and date, the telephone caller then must call the person, and the person must remember to be available to receive the telephone call. With this arrangement, two telephone calls are placed in order to achieve the telephone call at the specified future time and date, the first call to arrange the future time and date, and the second call at the future time and date.
With the above arrangement, the person to whom the telephone call is placed may not be available either when the telephone caller first attempts to arrange the future telephone call, or, once arranged, at the specified future time and date of the telephone call.
It would, therefore, be desirable to overcome the aforesaid and other disadvantages.